MB3771 Datasheet | Fujitsu Semiconductor Limited

FUJITSU SEMICONDUCTOR DATA SHEET DS04-27400-7E ASSP For power supply applications BIPOLAR Power Supply Monitor MB3771 s DESCRIPTION The Fujitsu MB3771 is designed to monitor the voltage level of one or two power supplies (+5 V and an arbitrary voltage) in a microprocessor circuit, memory board in large-size puter, for example. If the circuit’s power supply deviates more than a specified amount, then the MB3771 generates a reset signal to the microprocessor. Thus, the puter data is protected from accidental erasure. Using the MB3771 requires few external ponents. To monitor only a +5 V supply, the MB3771 requires the connection of one external capacitor. The level of an arbitrary detection voltage is determined by two external resistors. The MB3771 is available in an 8-pin Dual In-Line, Single In-Line Package or space saving Flat Package. s Features - - - - - - - - - Precision voltage detection (VSA = 4.2 V ± 2.5 %) User selectable threshold level with hysterisis (VSB = 1.23 V ± 1.5 %) Monitors the voltage of one or two power supplies (5 V and an arbitrary voltage, >1.23 V) Usable as over voltage detector Low voltage output for reset signal (VCC = 0.8 V typ.) Minimal number of external ponents (one capacitor min.) Low power dissipation (ICC = 0.35 m A typ., VCC = 5 V) Detection threshold voltage has hysteresis function Reference voltage is connectable. s PACKAGES 8-pin plastic DIP 8-pin plastic SIP 8-pin plastic SOIP (DIP-8P-M01) (SIP-8P-M03) (FPT-8P-M01) MB3771 s PIN ASSIGNMENT (FRONT VIEW) 8 (TOP VIEW) CT VSC OUTC GND 1 2 3 4 8 7 6 5 RESET VSA VSB /RESIN VCC 7 6 5 4 3 2 1 RESET VSA VSB / RESIN VCC GND OUTC VSC CT (DIP-8P-M01) (FPT-8P-M01) (SIP-8P-M03) s BLOCK DIAGRAM VCC 5 ≅ 1.24 V ≅ 1.24 V ≅ 100 kΩ VSA 7 ≅ 40 kΩ + - p. A + REFERENCE VOLTAGE + - R Q ≅ 12 µA ≅ 10 µA -...